It is generally known that polymeric materials have to be pretreated before chemical metallisation, for example by etching the polymer surface with chromosulphuric acids. This method is, however, applicable only to those polymers whose surface can be altered oxidatively with the formation of cavities and vacuoles.
It is furthermore known that working with chromosulphuric acid, SO.sub.3, vapor or other oxidants is accompanied by a deterioration of the physical properties such as the notched impact strength and the electrical surface resistance of the polymeric material. In addition, traces of hexavalent chromium, which rapidly result in poisoning of the metal baths, are often troublesome.
The known methods of electrolessly metallising materials comprise, however, several process steps and have the disadvantage that they are not directly applicable to all polymers. Often a chemical or physical roughening has to be carried out.
It has therefore already been proposed to activate the polymer surfaces very mildly with organometallic catalysts (cf. for example, U.S. Pat. No. 3,560,257 and EP-A 81,129). However, this method, which is very elegant per se, is not universally applicable either. In addition, the use of solvents frequently results in the initiation of stress-corrosion cracking of the polymer injection moulding which is under tensile or compressive stress.
Other methods such as those described in U.S. Pat. Nos. 3,560,257 and 4,017,265, and also DE-A 3,627,256 have the disadvantage that they require relatively large amounts of expensive noble-metal activators.